We propose to use high sensitivity differential scanning calorimetry and x-ray diffraction to study mixed lipid systems in the presence of CaC12 and NaC1. Specifically, systems of interest are lecithin-cholesterol, mixed lecithins, n-alkane-lecithin and glycolipid-lecithin. The ultimate objective is to elucidate miscibilty parameters for membrane components which will also explain the thermodynamic parameters of such systems. In particular, these studies are important in biological processes involving membrane fusion, lipid deposition and the interaction of anesthetics.